Caption: Computer reconstruction of the decay of a Z-naught particle, observed with the Mark II Vertex Detector of the Stanford Linear Collider (SLC). The Z- naught is one of the gauge bosons, and is the 'carrier' of the electroweak nuclear force. It is created by an electron/positron anihilation at energies of 93 GeV (giga electron volts). The Z- naught has decayed into hadrons (red tracks), which themselves have decayed into secondary hadrons (yellow tracks) and a muon (green track). The blue tracks show low-energy background events. The Z-naught was discovered at the European LEP accelerator in 1983.